Abstract
The vascular system of vertebrates consists of an organized, branched network of arteries, veins, and capillaries that penetrates all the tissues of the body. One of the most striking features of the vascular system is that its branching pattern is highly stereotyped, with major and secondary branches forming at specific sites and developing highly conserved organ-specific vascular patterns. The factors controlling vascular patterning are not yet completely understood. Recent studies have highlighted the anatomic and structural similarities between blood vessels and nerves. The 2 networks are often aligned, with nerve fibers and blood vessels following parallel routes. Furthermore, both systems require precise control over their guidance and growth. Several molecules with attractive and repulsive properties have been found to modulate the proper guidance of both nerves and blood vessels. These include the Semaphorins, the Slits, and the Netrins and their receptors. In this review, we describe the molecular mechanisms by which blood vessels and axons achieve proper path finding and the molecular cues that are involved in their guidance.
Highlights
The vascular system of vertebrates consists of an organized, branched network of arteries, veins, and capillaries that penetrates all the tissues of the body
Blood vessels are formed through 2 distinct mechanisms: vasculogenesis, which refers to the differentiation of primitive mesodermal cells into endothelial cells, and angiogenesis, a process by which endothelial cells proliferate and migrate to colonize tissues
We have found that among Netrin receptors, the repulsive type receptor Unc5b is selectively expressed in the endothelium of growing capillaries and participates in the regulation of vascular system morphogenesis, both during developmental and pathological angiogenesis (Figures 3 and 5).[28,107,108]
Summary
Hemodynamic force is necessary and sufficient to induce vessel remodeling in the yolk sac.[4] Experimental manipulation of blood flow in chick embryos by ligation of the major yolk sac artery leads to rerouting of blood flow and can transform yolk sac arteries into veins and vice versa.[5] These findings suggest that vessels are plastic with regard to their arterial or venous identity and that both appropriate hemodynamics and appropriate growth factor gradients are together required to shape the highly stereotyped vessel anatomy of vertebrate embryos Such stereotyped anatomy of vessels in the human body had already been observed several hundred years ago. We discuss the similarities in nerve and vessel patterning and how common molecular pathways regulate guidance of axons and vessels to distant sites
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
